Process of recording phonograph records



June 12, 192.8. 1,673,462

w. w. MCLAREN PROCESS OF RECORDING-FHONOGRAPH RECORDS Filed April 18, 1927 Patented June 12, I928.

-UNITED STATES PATENT OFFICE.

wmnrar't w. MOLABEN, or BIRMINGHAM, ALABAMA. rnoonss or nnconnme :anonoenarn :ancoans. I

Application filed April 18, 1927. Serial No. 184,656.

This invention aims to provide a novel process and means for making phonograph Y records.

It is within the province of the disclosure to improve generally and to enhance the utility of devices of that type to which the invention appertains.

With the above and other objects in view which willappear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and. claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the accompanying drawing, the invention is-shown In a single vertical sectional figure, wherein parts appear in elevation.

. In carrying out the invention, there is provided a receptacle 1 of any desired shape and size, supported on a base 2, acompres sible gasket-3 being interposed between the base 2 and the receptacle 1,clamps 4 holding the parts 1, 2- 'and 3 in air-tight relation. A pipe 5 is mounted atone end in the base 2 and is in communication with the receptacle 1, the outer end of the pipe 5 being connected to a pump 6 or other instrumentality whereby air may,be withdrawn from the receptacle 1, the. process beingcarried out in a vacuum, meaning thereby as close an approximation of a perfect vacuum as can be obtainediby known means. A shut-off valve 7 is interposed in the pipe 5, and a relief valve 8 is interposed in the said pipe, the valve 8 being disposed between the valve 7 and the receptacle 1. Conductors 9 are mounted airtight inthe side of the receptacle land are joined to terminals 10 which are accessible from inside the receptacle 1. Conductors 11 are mounted in the receptacle 1, in spaced relation to the conductors 9, and are joined to terminals 12 which'are accessible 'frominside the receptacle 1, the conductors 11 being adapted to cooperate with any well known electrical means for amplifying sound (not shown).

1 .On the base 2 is mounted the casing 14 of a motor which, preferably, is electrically V driven. The casing 1 is provided with spring contact tongues 15, adapted to cooperate withthe terminals 10 when the receptacle 1 is mounted on the base 2, as shown .of the stylus.

in the drawing. Owing "to the way in which the parts 15 and 10 cooperate, electric cur rent is supplied to operate the motor. There is a standard. 16 on the casing 14, the standard carrying spring switchtongues 17 which are insulated from eachother, the switch tonguesl? being adapted to cooperate with the terminals 12 in the Way hereinbefore' described in connection with the terminals 10 and the switch tongues 15. Conductors 18 lead from the switch tongues 17 to an elec trically operated recording mechanism 19 which is supported at 20 on the casing 14 in such a Way that the stylus 23 of the recording mechanism 19 may cooperate with a master record 21 carried by a turntable 22 which is operated by a motor in the casing 14.

In practical operation, when the parts are arranged as shown in the drawing, the air is withdrawn from the receptacle 1, by way of the pump 6 or its equivalent, and the shutoff valve 7 and the relief valve 8 are closed to maintain the vacuum or partial vacuum which has been obtained in the receptacle 1. The motor is operated by current derived from the conductors'9, or in any other suitable way, to rotate the turntable 22 and the record 21 with respect to the stylus 23 ofthe recording mechanism 19. The result isthat the master record is produced in vacuo. A' maximum effect of the stylus movement is obtained, there being no air-pocket in front Moreover, since there is-no circulation of air or draft, dirt, grit, and other foreign substances, cannot accumulate on the record or on the point of the stylus,

during. recording, toimpede the full and graph record, which consists in inscribing i 1n a vacuum.

2. In a device of the class described, an air-tight receptacle, means for'withdrawing air from the receptacle, a recording mechanism in the receptacle, and means for operating the recording mechanism from a point external to the receptacle.

In testimony that I claim the foregoing as my own, 1 have hereto aflixed my slgnature.

WELIAM W. MCLAREN.

ll A method of making a master phono 

